1. Field of the Invention
The present invention relates to golf balls. More particularly, the present invention relates to an improvement of the shape of dimples.
2. Description of the Related Art
Golf balls have numerous dimples on the surface thereof. A role of the dimples involves causing turbulent flow separation through disrupting the air flow around the golf ball during the flight. This role is referred to as a “dimple effect”. By causing the turbulent flow separation, a separating point of air from the golf ball shifts backwards leading to the reduction of a drag. The turbulent flow separation promotes the differentia between the separating points at the upper and lower sides of the golf ball, which result from the backspin, thereby enhancing the lift force that acts upon the golf ball. Excellent dimples disturb the air flow more efficiently.
Cross-sectional shape of the dimple affects flight performances of a golf ball. A variety of improvements of the cross-sectional shape of the dimples in an attempt to improve the flight performance have been proposed. U.S. Pat. No. 4,979,747 discloses a golf ball provided with dimples having a cross-sectional shape being a truncated cone. U.S. Pat. No. 5,338,039 discloses dimples having a great angle of inclination in the vicinity of the dimple edge while having a low angle of inclination in the vicinity of the center thereof.
Top concern to golf players for golf balls is the travel distance. In light of the flight performance, there remains room for an improvement of the cross-sectional shape of the dimple. An object of the present invention is to provide a golf ball that is excellent in the flight performance.